Dehydration in Newborns and Infants

Mother holding her hand to the forehead of her crying baby girl

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What Is Dehydration in Babies?

Dehydration is the state of not having enough fluid in the body for it to carry out its normal business.

Your baby's body is made up of approximately 75% water, which is a component of every cell. It is vital for temperature control, maintaining organ and tissue health, carrying nutrients to cells, and more.

Each day, your child loses water through urination, bowel movements, sweating, crying, and even breathing. It is replaced each time they eat or drink.

A number of things can throw off the balance between depletion and replenishment. For example, if your baby vomits or has diarrhea, they will lose fluid more rapidly than when they are well, potentially resulting in dehydration.

Types of Dehydration in Babies

Hydration isn't just about water. Instead, bodies need sufficient fluid levels as well as electrolytes, which are minerals, such as salt, that help regulate fluid balance.

There are three main types of dehydration:

  • Hypertonic or hypernatremic: Loss of water
  • Hypotonic or hyponatremic: Insufficient of electrolytes, which are the salts in your body
  • Isotonic or isonatremic: Low levels of both water and electrolytes

Signs of Dehydration in Babies

The most common signs of dehydration in babies include:

  • Concentrated urine that looks very dark yellow or orange
  • Constipation
  • Dry lips
  • Dry mouth
  • Dry mucous membranes
  • Excessive sleepiness
  • Irritability
  • Less than six wet diapers in a 24-hour period
  • No interest in taking a bottle or breastfeeding
  • No tears when crying
  • Paleness
  • Sunken fontanelle (soft spot) on their head
  • Wrinkled skin

Babies can become dehydrated quickly. Be on the lookout for these signs, especially when your baby is sick, overheated, or having trouble feeding (e.g., during a nursing strike or when teething).

Note, however, that babies can become dehydrated even when none of these concerns are at play.


A number of things can cause dehydration. While it can affect anyone at any age, it is more common in little ones than adults.

Among the reasons why: Kids' bodies are made up of more water (78% for newborns vs. about 60% in grown-ups). They also metabolize at a higher rate, meaning their bodies utilize water faster.

Among the reasons infants and newborns get dehydrated:

  • Breastfeeding issues: Breastfed babies can become dehydrated if they're not latching on correctly, not breastfeeding often enough or long enough, or there's an issue with breast milk supply.
  • Bottle-feeding issues: Bottle-fed babies may become dehydrated if they're not taking a bottle often enough or they're not taking in enough infant formula/pumped breast milk at each feeding.
  • Diarrhea: If your child develops diarrhea, fluid is lost with each bowel movement (sometimes significant amounts).
  • Fever: A rise in your child's body temperature can cause a greater loss of fluids. Plus, babies may not take feedings as well when they have a fever.
  • Overexposure to heat: High temperatures, extreme humidity, or spending too much time outdoors in the hot sun can cause sweating and the evaporation of fluids through your baby's skin.
  • Refusing to eat: Babies may refuse the breast or bottle if they are in pain or not feeling well. A stuffy nose, earache, or sore throat can interfere with sucking and swallowing.
  • Vomiting: When babies aren't able to keep down most of their feedings, they're losing important fluids that their body needs. Repeated vomiting can quickly lead to dehydration.

Dehydration in newborns and young infants is usually the result of not taking in enough fluids to replace what is lost in the course of the day.

Older infants and children are more likely to become dehydrated from an illness than newborns.


The treatment for infant dehydration depends on the cause and severity of the condition and the age of the baby. For newborns or young infants under 3 months old, your doctor will likely want to see the baby for a check-up. If diarrhea or other illness or condition been prolonged, the doctor will likely want to see your baby regardless of age.

If they are showing any possible signs of dehydration, call their doctor. Your doctor can let you know if your child needs to be seen and/or recommend appropriate treatment.

That said, severe dehydration can be a very dangerous and even life-threatening situation. So, don't hesitate to seek emergency care if signs are significant, you can't reach your doctor, or you are otherwise concerned.

Get immediate medical attention if your baby:

  • Seems to be struggling
  • Has a sunken fontanelle
  • Has diarrhea for more than eight hours
  • Is not breastfeeding or bottle feeding well
  • Is under 3 months old and has a fever
  • Is vomiting after two feedings in a row
  • Has other prolonged or severe signs of dehydration

At Home

If your child's symptoms are mild, your doctor may tell you to begin treating your child at home while continuing to carefully monitor their symptoms.

You'll likely be advised to follow these steps:

  • Keep track of your baby's feedings and wet diapers.
  • Move your baby to a cool place and remove excessive clothing or blankets from your child if the temperature is very warm and your baby is overheating.
  • Offer a bottle or breastfeed frequently, especially if your baby isn't taking in very much at each feeding.
  • Wait on other drinks. Do not give your baby an oral rehydration fluid (e.g., Pedialyte), water, juice, or soda for illness, vomiting, or diarrhea without talking to your doctor first. Aside from the fact that these drinks may not be age-appropriate, giving them the wrong liquid and/or amounts can worsen dehydration.

If your child's pediatrician recommends oral rehydration fluid, follow their instructions. These fluids are different from others drinks in that they contain electrolytes and are specially designed to rehydrate quickly.

At the Doctor's Office

If your doctor advises you to bring your baby in for a check-up, they will do a thorough evaluation of your baby to determine the best course of treatment.

For breastfeeding parents, the doctor may want to check your baby's latch and breastfeeding technique. If you're breastfeeding and your baby isn't getting enough breast milk, you may be advised to consult with a lactation consultant and/or to supplement your baby with infant formula.

The doctor will also examine your child's overall health. If the baby has an infection, the doctor may prescribe medicine to treat the illness.

At the Hospital

If the dehydration becomes severe, your child may need to go to the hospital.

There, the doctor can monitor your baby's intake and output of fluids. They may also give your baby IV fluids to replace what has been lost, especially if the baby is not eating well or has severe vomiting and diarrhea.

They may also prescribe medicine for your child to treat any illness or underlying cause.


The best way to prevent dehydration is to not only know the signs and understand the causes but to also know how to keep it from happening.

Feed Your Newborn Frequently

If you're bottle-feeding, offer one to three ounces of infant formula or pumped breast milk in a bottle every two to three hours.

If you're breastfeeding, put your baby to your breast at least every two to three hours around the clock. Wake sleepy newborns up to breastfeed or to take their bottle if it's been more than three hours.

As the weeks go on and your baby begins to take more at each feeding, they may be able to sleep longer between feedings.

Do not stop feeding your child to try to stop diarrhea or vomiting. Your baby needs extra fluids to replace what they're losing, so continue to breastfeed or bottle-feed as often as possible while your child is ill and recovering.

Monitor Wet Diapers and Weight Gain

Keep track of the number of wet diapers your baby is having each day and see your baby's doctor for regular well-baby checkups to monitor for healthy weight gain.

Stay Out of Extreme Heat

Try not to take your newborn or young infant outdoors if it's very hot or humid. If you need to be outside, keep your baby in the shade and as cool as possible.

Babies can also overheat inside in a hot, stuffy room or car, or if they're all bundled up. Try to keep your baby comfortable and breastfeed and offer a bottle often to replace the fluids that they're losing.

Avoid Giving Water

You don't have to give your baby a bottle of water between feedings to try to prevent dehydration. In fact, it's best not to unless otherwise directed by your doctor.

Water fills the baby up and doesn't provide any nutrients. Both breast milk and infant formula provide your baby with fluid plus nutrition.

Furthermore, the American Academy of Pediatrics says that babies should only be given water starting at age 6 months, and that their daily consumption should be limited to 4 to 8 ounces.

If it's a very hot day or you think your baby needs extra hydration, you can give them an extra bottle of formula or pumped breast milk or breastfeed them more often.

Prevent the Spread of Germs

Wash your hands often, especially before preparing your child's bottle and after changing diapers or using the bathroom. Keep hand sanitizer handy.

Remind family members and friends to wash their hands, and ask them not to visit your child if they are sick—particularly when your child is a newborn and young infant.

A Word From Verywell

Babies lose fluids during the day, but they get all the fluids they need to replace what's lost through their regular feedings.

It's a natural balance. When there's a shift, a baby can easily become dehydrated. By understanding this common condition, its causes, and it's warning signs, you can try to prevent it or at least catch it early.

Always check with your baby’s doctor if you see signs of dehydration or even just are concerned about their eating patterns, weight gain, or hydration level.

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9 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. C.S. Mott Children's Hospital. University of Michigan Health. Dehydration. February 26, 2020.

  2. Mayo Clinic Health System. Water: essential to your body. July 22, 2020.

  3. American Academy of Pediatrics. Signs of dehydration in infants & children

  4. Anigilaje EA. Management of diarrhoeal dehydration in childhood: a review for clinicians in developing countriesFront Pediatr. 2018;6:28. doi:10.3389/fped.2018.00028

  5. Rocky Mountain Hospital for Children. When to take your child to the ER for dehydration.

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  9. Muth, ND. American Academy of Pediatrics. Recommended drinks for young children ages 0-5. September 18, 2019.

Additional Reading
  • American Academy of Pediatrics. New Mother’s Guide to Breastfeeding. Bantam Books. New York. 2011.

  • Lawrence, Ruth A., MD, Lawrence, Robert M., MD. Breastfeeding: A Guide for the Medical Profession, Eighth Edition. Elsevier Health Sciences. 2015.

  • Riordan, J., and Wambach, K. Breastfeeding and Human Lactation, Fourth Edition. Jones and Bartlett Learning. 2014.